Hairstyling products such as hairsprays are used for achieving different hairstyles and for holding hair strands in place for a period of time. Typically, hairsprays comprise film-forming polymers, which when applied to keratin-containing fibres, such as human hair, form fibre-fibre welds. These welds ‘glue’ the fibres together and hence impart hold to the hairstyle.
Aerosol hairspray products usually comprise a pressure-resistant container, a nozzle, a propellant, and a hairstyling formulation. A hairspray composition is normally ejected from such products via aerosol-forming nozzle. See, for example, US2009/0104138A1. Alcohols are normally used in the hairstyling formulation, for example to reduce surface tension. However, a high proportion of alcohol may leave the hair feeling dry and brittle and some alcohols may cause an allergic response in some users. In addition ethanol is a VOC, volatile organic compound, which can accumulate in the environment and cause environmental concerns. Also, ethanol is flammable.
Shernov et al in U.S. Pat. No. 5,304,368A (“Shernov”, hereinafter) relates to a non-foaming, non-viscous, alcohol-free, water-based pressurized hair-fixative spray product for use as the total fill in an aerosol container by delivery from an actuated-valve of predetermined dimensions, particularly the vapor tap and stem orifice sizes. Birkel et al in US2013/0068849A1 (“Birkel”, hereinafter) relates to an aerosol hairspray product for styling and/or shaping hair wherein the product comprises: a container; a spraying device; a propellant; a hairstyling formulation comprising: (a) at least about 50% water; and (b) from about 0.01% to about 20% of a hairstyling polymer, wherein the hairstyling polymer is selected from the group consisting of: acrylates copolymers of two or more monomers of (meth)acrylic acid or one of their simple esters; acrylateslhydroxyesters acrylates copolymers of butyl acrylate, methyl methacrylate, methacrylic acid, ethyl acrylate and hydroxyethyl methacrylate; polyurethane-14/AMP-acrylates polymer blend; and mixtures thereof. Harman in US2009/0124961A1 (“Harman”, hereinafter) relates to a steam-sterilizable aerosol valve [that] has a valve body of polymeric material such as polyphenylene sulfone (PPSU) having an HDT (heat deflection temperature) at 1.8 MPa stress in the range of 200-275° C.
There is a constant need, therefore, for more environmentally friendly, more sustainable, less harsh and more affordable hairspray products. However, altering one or more features of an aerosol hairspray product can be challenging since the interrelationship therebetween affects the product performance. For example, utilising a different propellant may result in an unacceptable decrease in package operating pressure resulting in an increased product wetness on application, drying time and particle size distribution and consequently unsatisfactory hold.
When considering the aforementioned needs when designing such improved hairsprays, therefore, good hairspray performance should be maintained. Performance benefits may include, for example: excellent hold; long-lasting hold; good humidity resistance; shapeable hold; acceptable drying time; excellent soft, natural hair feel; acceptable and/or non-stickiness/tackiness of the hands and hair. Of particular relevance to consumers is excellent hold without stickiness and an acceptable drying time.